Multiple texts sent by galaxy s5

[AC Question]

I'm using the default texting app on my galaxy s5. Service is through sprint and I have a full signal. When I send a text to both iPhone and Android users on sprint and on Verizon they will receive the text between 2 and 4 times while the spinning wheel on my s5 indicates that it's still trying to send the text. In some cases it tells me the send failed even though the recipient got the text 4 times. How do I fix this?